Found direction
Now I know how crucial it is, not to lose sight of the goal.. I forgot the whole reason why we're trying to get
dm to work with RAID devices .. 'cuz with
md, you can't take a snapshot!!! I I just went to talk to Manu, to tell him I wuz stuck.. n' was reminded of this!!
MD
I've been reading through some storage-related websites. At my interview, I remember claiming to know a bit about computer hardware. The interviewer proceeded to ask me what I knew about ways of connecting a hard drive and I talked about IDE and SCSI, and tho' I didn't even know what they stood for, I remarked that the latter was better. I shot in the dark with an insane mumbling of 'Integrated Development Environment', but immediately realised my mistake and admitted it. Today, I came across a couple of good pages on
SCSI vs.
IDE.
I've also been browsing through a lot of MD code (MD is an EVMS plugin) lately. Manu came over today n' we cracked our heads trying to find out the flow from the Engine, through the InternalAPI, to the setting up of the plugins by loading them as modules. My current task is to understand how the
MDRegMgr decides what to call.. linear, raid0, raid1, raid5 or multipath...
Update: It doesn't. You have to call MDRaid1RegMgr for eg.
I'm back !!
The top-secret thingy is almost scrapped. So' I'm back to the
Linux Snapshot Driver project! Yippee!! :D
Reading code again to try n' find out where EVMS uses MD for RAID1. My task is to get DM to do this instead.. My "walking through the code" has taken me a few steps ahead. Discovered
Dm.c n'
Devmapper.h which talk about stuff I need to know. On an impulse, I searched for Md n' Voila! Hit upon
Md.h.. I coulda kicked myself for not finding this stuff earlier!
Also found a perl module
MD.pm, which I'm trying to decipher..
